Optical wavelength multiplexing transmission apparatus and optical output control method for optical wavelength multiplexing transmission apparatus

Abstract

The present invention provides an optical wavelength multiplexing transmission apparatus and an optical output control method for an optical wavelength multiplexing transmission apparatus in an optical wavelength multiplexing transmission system using a main signal light and an OSC light. The optical wavelength multiplexing transmission apparatus ( 10 a ) is made up of a first transmitting/receiving section ( 52 a ) a second transmitting/receiving section ( 52 b ) and an apparatus supervisory control unit ( 54 ). This can not only achieve quick restoration from troubles, but also stably calculate an optical output level even if a change of the number of wavelengths to be multiplexed takes place in a main signal light, and even save troublesome adjustments for the improvement of reliability of a transmission line while eliminating the need for a signal source for the adjustment of a receive optical level at the initial installation.

1. An apparatus comprising:
 an optical device positioned along an optical transmission line, comprising a sub-signal transmitter transmitting a sub-signal light to a downstream side optical device through the optical transmission line; and 
 a controller calculating a loss in the transmission line in accordance with the sub-signal light as received by the downstream side optical device and the sub-signal light to be transmitted by the sub-signal transmitter, by monitoring both of a transmission output level of the sub-signal light from the sub-signal transmitter and a reception input level of the sub-signal light at the downstream side optical device. 
 
   
   
     2. An apparatus as in  claim 1 , wherein, in accordance with the calculated loss, the controller adjusts a power level of main signal light output from the optical device and to be transmitted downstream of the optical device. 
   
   
     3. An apparatus as in  claim 1 , further comprising:
 an optical amplifier optically amplifying main signal light to be output from the optical device and to be transmitted downstream of the optical device, wherein the controller controls the optical amplifier to adjust a power level of the main signal light in accordance with the calculated loss. 
 
   
   
     4. An apparatus comprising:
 an optical device positioned along an optical transmission line, comprising a sub-signal transmitter transmitting a sub-signal light to a downstream side optical device through the optical transmission line; 
 an optical amplifier amplifying main signal light transmitted through the transmission line; and 
 a controller calculating a loss in the transmission line in accordance with the sub-signal light received by the downstream side optical device and the sub-signal light to be transmitted from the sub-signal transmitter, by monitoring both of a transmission output level from the sub-signal transmitter and a reception input level of the downstream side optical device of the sub-signal light, and controlling the optical amplifier in accordance with the calculated loss to adjust a power level of the amplified main signal. 
 
   
   
     5. An apparatus comprising:
 an optical device positioned along an optical transmission line, comprising a sub-signal transmitter transmitting a sub-signal light to a downstream side optical device through the optical transmission line; 
 an optical amplifier amplifying main signal light transmitted through the transmission line; and 
 means for calculating a loss in the transmission line in accordance with the sub-signal light received by the downstream side optical device and the sub-signal light to be transmitted from the sub-signal transmitter, by monitoring both a transmission output level from the sub-signal transmitter and a reception input level of the downstream side optical device of the sub-signal light, and for controlling the optical amplifier in accordance with the calculated loss to adjust a power level of the amplified main signal. 
 
   
   
     6. An optical transmission system comprising:
 first and second optical devices connected to each other through first and second optical transmission lines, the first optical device comprising a first sub-signal transmitter transmitting a first sub-signal light to the second optical device through the first optical transmission line; and 
 a controller calculating a loss in the first transmission line in accordance with the first sub-signal light received by the second optical device and the first sub-signal light to be transmitted by the first sub-signal transmitter, by monitoring both a transmission output level from the first sub-signal transmitter and a reception input level of the second optical device of the first sub-signal light. 
 
   
   
     7. The optical transmission system as in  claim 6 , wherein
 the first optical device comprises a first monitor monitoring the transmission output level of the first sub-signal light from the first sub-signal transmitter, and 
 the second optical device comprises a second monitor monitoring the reception input level of the first sub-signal light at the second optical device; and 
 the system further comprises a second sub-signal transmitter transmitting a second sub-signal light to the controller through the second optical transmission line, the second sub-signal light including information indicating the reception input level of the first sub-signal light monitored by the second monitor.